NfdTest.java

import static org.hamcrest.CoreMatchers.*;
import static org.hamcrest.MatcherAssert.*;

import java.text.Normalizer;
import java.text.Normalizer.Form;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

import org.junit.Test;


public class NfdTest {


    @Test
    public void existsNfdChar1() {
        assertThat(Normalizer.isNormalized("ポケモン", Normalizer.Form.NFC), is(true));
        assertThat(Normalizer.isNormalized("ポケモン", Normalizer.Form.NFC), is(false));
        String normalized = Normalizer.normalize("ポケモン", Normalizer.Form.NFC);
        assertThat(Normalizer.isNormalized(normalized, Normalizer.Form.NFC), is(true));
        assertThat(normalized, is("ポケモン"));
    }

    private static final List<Normalizer.Form> FORMS = Arrays.asList(Form.values());
    private Form detectNormalization(String s) {
        return FORMS.stream().map(form -> Normalizer.isNormalized(s, form) ? form : null)
                .filter(Objects::nonNull).findFirst().get();
    }

    @Test
    public void existsNfdChar2() {
        String str = "ポケモンポケモン";
        System.out.println(String.join("\n", str.codePoints().mapToObj(codepoint -> {
            String s = String.valueOf(Character.toChars(codepoint));
            return s + " : " + detectNormalization(s).name();
        }).collect(Collectors.toList())));

        /*
            ポ : NFC
            ケ : NFD
            モ : NFD
            ン : NFD
            ホ : NFD
            ゚ : NFD
            ケ : NFD
            モ : NFD
            ン : NFD
         */
    }

    @Test
    public void existsNfdChar3() {
        String str = "ポケモンポケモン";
        System.out.println(String.join("\n", IntStream.range(0, str.length()).mapToObj(index -> {
            String s = String.valueOf(str.charAt(index));
            return s + " : " + detectNormalization(s).name();
        }).collect(Collectors.toList())));

        /*
            ポ : NFC
            ケ : NFD
            モ : NFD
            ン : NFD
            ホ : NFD
            ゚ : NFD
            ケ : NFD
            モ : NFD
            ン : NFD
         */

        // こっちでも変わらない
        System.out.println(String.join("\n", str.chars().mapToObj(codepoint -> {
            String s = String.valueOf(Character.toChars(codepoint));
            return s + " : " + detectNormalization(s).name();
        }).collect(Collectors.toList())));

        /*
            ポ : NFC
            ケ : NFD
            モ : NFD
            ン : NFD
            ホ : NFD
            ゚ : NFD
            ケ : NFD
            モ : NFD
            ン : NFD
         */
    }

}